fix crash when digitizing a part and adding it to a (cached) single part geometry

Author: jef-n

python/plugins/processing/tests/PackagingTests.py

@@ -27,8 +27,8 @@ def testGrass(self):
 
     def testOtb(self):
         folder = OTBUtils.findOtbPath()
-        self.assertIsNotNone(folder)            
+        self.assertIsNotNone(folder)
 
 def runTests():
     t = unittest.TestLoader().loadTestsFromTestCase(PackageTests)
-    unittest.TextTestRunner(verbosity=3, stream=sys.stdout).run(t)
+    unittest.TextTestRunner(verbosity=3, stream=sys.stdout).run(t)

src/core/geometry/qgsgeometry.cpp

@@ -904,8 +904,8 @@ bool QgsGeometry::convertToMultiType()
     return false;
   }
 
+  detach( true );
   multiGeom->addGeometry( d->geometry );
-  detach( false );
   d->geometry = multiGeom;
   removeWkbGeos();
   return true;